It is well known to use expendable cores (e.g., sand, salt, etc.) to define internal features of metal castings. For example, resin-bonded sand cores are used to define the cooling jacket in internal combustion engine blocks. Molten metal is cast about the core, and, following solidification, the core is removed by mechanical, thermal, or chemical means. It is likewise well known to position and hold the cores in the die cavity by means of so-called "core print(s)" which are projections extending from the core and which mate with conforming pockets in the wall(s) of the die defining the molding cavity.
Many cores, and particularly sand cores, are quite friable particularly after having been heated to the casting temperature of the metal. As a result, when the die is opened and the casting removed, pieces of the core print can break off and remain in the pockets which interferes with proper positioning of the next core print.
The present invention overcomes the aforesaid difficulties by providing a self-cleaning core print for insuring that all of the core print material is removed from the die pocket therefor.